ST. JOSEPH, Mo. (AP) - The question lobbed from the back of the media scrum was something of a throwaway, one last query for Chiefs linebacker Derrick Johnson as he headed from the practice field to the locker room.

It wound up stopping him in his tracks.

''You're 32. Have you given any thought to how much time you want to keep doing this?''

On Nov. 22, to be exact. But what could have been an awkward moment was immediately defused by the effervescent smile that Johnson plastered on his face, one that seems to be permanently affixed these days.

The veteran is beginning his 10th season, coming off his third Pro Bowl, and closing in on the franchise record for tackles - he needs 19 to reach 1,000 for his career, which would be one more than Gary Spani recorded from 1978-86.

He still believes his best days are ahead of him, even if the first strands of gray hair are lurking in the shadows.

''No, it hasn't crossed my mind,'' Johnson continued, when asked about retirement. ''I've been fortunate and blessed not to have a major injury. Every year, when I go back to work out with Jamaal (Charles) and all of these guys. If I can keep up with these guys, I can come back.''

Besides, age is just a number at his position. Ray Lewis and London Fletcher were both playing at a high level when they retired at age 38. Keith Brooking, Mike Peterson and Vonnie Holliday were also hanging around in their late 30s, though their play had begun to taper off.

There have been no signs of that happening with Johnson's play.

''He has a unique skill set. He has great range and great speed for a linebacker, which allows us to do a lot of things,'' Chiefs defensive coordinator Bob Sutton said.

''Any time you have speed, a lot of times the things that go unnoticed are the plays you prevent. Sometimes, a 5-yard gain stays 5 yards because you have the speed to be over there to make a tackle.

''In the time I've been here,'' said Sutton, who was hired last year, ''he has improved all the time, which has kind of been his trademark since he's been in the league.''

Indeed, if there is any constant on the Chiefs defense, it is No. 56 in the middle of the linebacker group.

After falling out of favor with former coach Todd Haley in 2009, and regaining his starting job the following year, Johnson has started every game with the exception of last season's finale, a meaningless game in which current coach Andy Reid rested nearly every starter.

Along the way, Johnson has put together four straight seasons of at least 100 tackles, picked off five passes and put relentless heat on unsuspecting quarterbacks.

He's managed to do it through a revolving door of head coaches and defensive coordinators, too, and even teammates at his own position. He's had four different linebackers start alongside him over the past two seasons, and will likely have another one in Joe Mays when this season kicks off.

''He's been just a big-time playmaker,'' Mays said. ''Now, I'm trying to pick his brain so I can get the chance to be where he's at, doing things that he's been doing on the field.''

Does it matter who is playing next to him?

''Does not matter, does not matter. This league is about change, how you adjust, and people change around the league all the time,'' Johnson said, shaking his head. ''When they come in, the veterans get them acclimated to the system and just go.''

Go, go, go. That's been Johnson's mantra since his days wrecking running backs at Texas, when he made a name for himself as one of the nation's premier linebackers.

And it was that constant pursuit of unparalleled perfection that made him a first-round draft choice in 2005, when Chiefs rookie De'Anthony Thomas was still playing Pop Warner football in Los Angeles.

''He's a pro, in every aspect of it. He's a pro,'' Reid said. ''Just handles everything the right way: classroom, on the field, off the field. He's top-notch.''

Back to that question about retirement, though.

Johnson is only signed through next season, which makes his long-term future uncertain. Will the Chiefs be willing to give him anything more than year-to-year deals? Will any team? And will he still have the same drive to keep playing the game at the highest of levels.

''I've been blessed to be with the Chiefs for this long,'' he said. ''The main part is staying healthy, being out there, being accountable, being responsible, staying on the field when they need me. ... You've never arrived. There is always room to get better.''